Hydraulic shutoff valve



June 16, 1953 H, w. wlsHART 2,642,079

HYDRAULIC SHUTOFF VALVE Filed Jag. 8. 1947 FIG. l sa4 3| 3s 51 4o 51 lllllllll.

4a 34 4s 36 se FIG. 2

4 FIG'. 3

'6 6 INVENIOR.

HERBERT W. WISHART BY I c.- @Aw/6x m A TTORN E Y Patented June 16, 1953 y 2,642,079 HYDRAULIC SHUTOFF VALVE Herbert W, Wisliart, University City, Mo., assignor to Curtiss-Wright Corporation, a corporation of Delaware Application January 8, 1947, Serial No. 720,697

This invention relates to Iluid valves and more particularly to an automatic hydraulic shut-ofi valve or fuse of the quantity-measuring type.

In hydraulic systems of aircraft there is the constant danger of ruptured lines cause by gunre, excessive vibration or other means, such rupture resulting in the inactivation of the equipment connected by the ruptured lines' and loss of the iluid supply. There are valves available of both the return-flow and quantity-measuring type for use in hydraulic systems to .stop the llowV therein in the event such rupture occurs. The valve of this invention relates to the quantity-measuring or metering type wherein a valve poppet is caused to move toward closed position by a proportioning of the fluid flow within the valve. The flow is so proportioned that passage through the valve of a predetermined quantity of fluid, sum-cient to actuate the fluid-operated apparatus of the system through one normal operation, will allow the poppet to remainunseated. However, should a rupture occur in the line between the valve and the fluid-operated apparatus, resulting in al greater quantity of fluid `passing through the valve, the poppet will be seated and prevent fur- Vther loss of fluid.

- valve in the system is closed at or prior to the end of one normal operation, the shut-off valve is' automatically reset, being returned to a full open position in readiness for the next operation of the system. At the beginning of such operation, i. e. when the control valveis opened, the shut-off valve will gradually move toward closed position until at the end of the operation a condition of balanceV is achieved with the valve still inpartially open position. Should this balance be destroyed by excessive flow, as will occur upon a rupture in the system, the shut-off valve will continue to move until it is fully closed. After such closing it will require manual resetting. which may be accomplished after the ruptured part of the system has been isolated or repaired.

The-foregoing and other objects and advantages will become apparent from the following description of the typical embodiment of the invention shown in the accompanying drawings, wherein: o

Figure 1 is a longitudinal sectional view through the metering shut-off valve; y

Figure 2 is an elevational view, partly in longitudinal section taken approximately in a plane approximately-at right angles to that of Figure 6 Claims. (Cl. 137-219) Figure 3 is a diagram illustrating one kind of system in which the shut-off valve may be em- Iployed.

As shown in the latter view the system may include a reservoir I I for hydraulic fluid, a pump I2 which is usually of the positive displacement type, a pressure accumulator I3, metering shutoil valves designa-ted I4 and I4', control valves I5 and I5 and fluid pressure operated devices I6v and I1, and I6 and I'I. These devices may comprise, for example, actuators for the wheel brakes of an aircraft, those indicated at I6 and I'I being for one set of brakes on left and right wheels, respectively, and those indicated at I6 and I'I for another set of brakes on the same two Wheels. Fluid drawn from the reservoir through conduit I8 is |directed under pressure to the shut-oil valves by conduit I9, the accumulator being provided to stabilize the fluid pressure and provide a source of pressure .when the pump is not operating. From the outlet of theshut-off valves the fluid passes through conduits 20 to the control valves I5 and I5 by which it is directed at the desired rates Ithrough conduits 2I and 22 to the one set of brake actuators I6 and I'I, and throughcon# duits 2I and 22. to the other set of actuators I-I and I1. A valve operating linkage 23 may be provided to control the passage of fluid to the left wheel brake actuators and a similar linkage 24 for fluid to the right Wheel brake actuators. The f valves I5 and I5', whose detailed construction forms no part of the present invention, are preferably such as to direct return llow of fluid from the brake actuators to a line 25 leading to the reservoir I I. The return flow is not through the shut-off valves.

It will be understood that the shut-oil valves I4, I4' will normally be fully open at the beginning of any operation of the system; that in operation the control valves I5 and I5 may be opened to allow iluid to pass to either or both sets of actuatorsvl, I6 and I'I, I'I; and that upon full operation of the latter or upon closing of valves I5, I 5 flow of fluid from the source through the shut-off valves I4, I4' will cease. Upon closing of valves I5, I5 from the source fluid in the actuators may return through lines 2 I, 2 I', 22, 22' to valves I5, I5 and through them and line 25 to the reservoir. Should any one of the actuators or the lines connected thereto be ruptured or develop a severe leak while the related valve I5 or I5 is open, fluid could be lost from the system to an extent which would render the entire system inoperativewere it not for the shut-off valves I4, I4 which will now be described in detail.

The body of each shut-off valve comprises tubuthreaded nipple extension i2 that is adapted rfor connection to a conduit such as te. p

Supported by the partition member 3.6 Vvandertending longitudinally within chamber is a sleeve 43. The joint between the partition and sleeve is sealed by a packingri'ng (is, which like the packings 33 and Iii! is preferably of theliexible O ring type seated in a groove that is slightly shallower and somewhat wider than the crosssection diameter of the ring when uncompressed. The opposite end of the sleeve i3 is provided with relatively large openings t5 providing free iiuid communication between the interior of the sleeve and the surrounding chamber 35. Slidable in the sleeve is a piston having a projection provided with a frusto-conical valve face 4l adapted v to close vupon the valve seat fl l. The valve face projects rom the body of the piston a distance sufficient tao-prevent closure of the openings G5, as may be seen inFigure 2.

Connected to the piston is a rod 48 which extends through an opening is in wall 436 of suflicient ldiameter to provide a metering passage for fluid around the rod and through the wall. The rod also extends through aligned openings in the endvvall of body section 3l and a part 52 secured thereto. Part 52 supports a tubular housing 53 for piston rod te and a collar 54 that is secured to the outer end of the rod. The openings for rod 48 through parts 3l and 52 may be sealedby a packing ring 55 which may be similar to theapackings hereinbefore described. Preferably the collar'5ll and piston it have lateral play relative to the rodv 13, to avoid possible binding ofthe parts. The play is provided by connections which comprise transverse pins 55 extending through thefrod. The piston may comprise an inner sleeve 5l secured to the outer shell by a retainer ring 58, as shown in Figure l, and the piston constitutes a movable wall dividing the cylinder in which it operates into opposed chambers of which one is contracted and the other expanded upon piston movement in either direction.

Pivoted by a pin 59 to part 52 isa manual reset lhandlel'il. The handle has a forked end 62 engageable with the collar 54. Such engagement may be effected when valve l'iis vclosed by depression of the handle, i. e. clockwise movement ofthe handle about pivot 59 as the parts appear in Figure 2. A spring 63 seated in a recess E4 resists such movement of the handle.

'During a normal operation of the branch system related to the shut-off valve, iiuid under pressure enters chamber 313 through inlet 38. A portion of this fluid passes through metering orifices 31 into chamber 35, while the remaining portionpasses through annular metering passage 49 into the interior of tube 43, moving the piston 4B toward valve seat 4l. Because of the large openings 135 the pressure in chamber 35 and Within thel outlet end of tube 43 will be substantiallyequal at all times. `The quantity of fluid passing through orifices 3l compared with the quantity passing-throughorince 49 will .depend .lo i

. when sufcient fluid has passed from valve I4 to 4 upon the relative flow capacities of these orifices, and will be substantially independent of variations in temperature and viscosity of the hydraulic fluid in the system. Consequently the fluid discharged through outlet 39 will consist partly of a proportioned quantity from chamber S5 and partly of another proportioned quantity of iiuid displaced by the piston t5 during its movement toward the valve seat.

.The orifices Sl and 19 are so proportioned that fully operate the associated fluid actuators i6 and il lthe piston-valve, e6, fil' has not yet reached its seat ci. Consequently when the operation has been completed or valve I5 has been closed, and flow through the valve i4 has consequently ceased, the pressures on opposite sides of partition vmember 36 will equalize. Thereupon the piston E will be moved-to its initial position, to the position shown Vin Figure 1, due to the difference in eiective areas of the opposite faces oi the piston resulting from the extension of the piston rod through the'casing wall. Inthis'way the valve It is automatically reset 'for a subsequent operation of the system Vat the conclusion of each normal operation or partial operation.

Should a rupture or excessive leakage occur in the system. downstream of the shut-off valve, there will be no cessation of fluid flow through the valve to equalize the pressures on opposite faces of the piston. Consequently in this event the valve lil rwill continue to advance and will close upon theseat, thereby preventing further loss of fluid. Once closed the valve will remain so until manually reset'due to reduction, in the area exposed to source pressureI of the piston surface facing fthe outlet.

Upon repair or isolation of the-ruptured part of the systemthe valve may be manually reset byv depressing handle 5l. This action'will cause the collar 5d to be engaged and moved to the left by fork 52, thereby vunseating thev valve. As soon asthevpressures on opposite faces of. piston llt substantially equalize, which will occur-as soon as the connected part of the system downstream of the unit ill is filled with fluid, the normal operating condition described hereinbefore will again prevail, and the reset handle maybe released.

It will thus be seen that there is provided a manual reset means by` which the system may be restored to normal operation after correction of a condition causing loss of fluid from the system. Automatic resetting, however, results when'ow is interrupted, as has been described.' The manual resetting of thepiston-valve d5, 4l vis efiected throughshifting axially thesame piston rod 48 which serves to produce the unbalance of the effective areas of the-'opposite faces-ofthe piston that is necessary to the normal functioning of the device. Y Y Y It will be understood thatvthe characteristics of the valverunit may be changed materially by varying the dimensions of orifices 3i and .fiilin relation to the volume of-flow necessary to operate the particular system in which the shut-oft' valve is used, and also in the dimensions of orces 3l and relative to eachother. For example, both orices shouldbe of sufficiently small size so that when there is a relatively small flow through the valvea-pressure differential will exist on opposite faces ofthe piston. This is necessary to overcome the effect ofthe difference in effective areas of the piston yfaces and soallow the piston' to move toward valve-closing position. 'As to relative dimensions of the orifices, if the 2l/rea;

of orifice 149 is reduced relative to the' total' 'areas of orifices 3,7., a 'greaterproportion of thefiuid flow will be through orifices 31 andv less through passage 49. This will mean that a greater volume of fluid will Jbe required to pass through vthe valve unit to complete a stroke of the piston-valve from fullyopened toA fully closed position. ,If the.

orifice 49 should be made relatively much larger so as to have little or no metering effect, the device would not operate in the manner hereinbefore described, responsive to quantity of fluid flow, vbut insteadwould be responsive to rate of fiow. That is, the valve would close only inthepresenceof a rate of flow such that the restriction of orifices 31 would cause enough pressure differential between chambersV 34 and 3'5`to overcome the effect of thediiferent effective areas of the opposite faces of the piston-valve. Y It will beV understood from the foregoingvdescription and statement of operation thatthe same device lll-may be adapted to different sys- 'tems requiring widely different quantities of fluid for one operation or requiring different minimum rates of flow by simply replacing the single partition member 36 with a similar member having differently sized or proportioned orifices 31 and 49. Such replacement may be effected by unscrewng the sections 3l and 32, no other fastening meansbeing used to hold the partition member in place.

It will be understood further that the specific system and shut-off valve structure shown and described herein merely illustrates one embodiment of the inventive principles that are involved, and that these principles may be utilized in other physical embodiments without departing from the spirit of the invention or from the scope of the appended claims.

I claim:

l. An automatic shut-off valve comprising a cylinder having a piston fitted thereto for sliding, an outlet at one end of said cylinder comprising a valve seat coaxial with the cylinder, a valve on said piston engageable with said seat, the Valve and seat diameter being less than that of 'said cylinder, said cylinder toward the outlet end thereof having an inlet opening from the cylinder i exterior to the cylinder interior whereby when said valve is off its seat fluid may flow through said inlet openings to said outlet; a piston rod extending from said piston through the other end of said cylinder, means providing a restricted inlet opening to said other end of the cylinder, p

and means for feeding both said inlet with pressure fluid.

2. In a metering shut-off valve, a valve casing having an inlet adjacent the upstream end thereof and an annular valve seat at the other downstream end thereof, the seat leading to an out-Y let, a cylinder disposed in said casing in axial alignment with the valve seat and spaced radially from the casing to provide a substantially annular passage around the cylinder, a cylinder coaxial fluid metering opening from the casing inlet into the interior of the cylinder at its upstream end, said wall having'a metering orifice therein connecting the inlet and outlet through said annular passage, a piston in vsaid cylinder having at its upstream end a piston rod of less diameter than the piston and of less diameter than said coaxial opening, said rod extending through said opening and through the casing, the net areas of the opening and orifice being so related as to divide fluid flow, part to the Vannular passage and part to the cylinder, the piston on openings 4its downstream end' having a valveextension of reduced diameter closable upon said valve seat,I

said cylinder having an `opening Ytherein at its extreme downstream end establishing communication between said annular passage and the cylinder interior adjacent the valve seat.

3. In a metering shut-off valve, a casing vcomprising a first section having an upstream chamber with a iiuid inlet and a second section having a downstream chamber with a uid outlet,v

said inlet and outlet being in the respective section walls, means connecting said `sections together, means secured between said sections and yconstituting a wall between said vupstream and downstream chambers, saidwall having formed therein a first metering orifice connecting said chambers, a cylinder supported by said wall and disposed within saiddownstream chamber, the interior of said cylinder at its downstream end communicating freely v with rsaid downstream` piston rod extending from the upstream end-0f the piston through said partition and through said first section to the exterior thereof, said rod reducing the effective area of the upstream side of the piston to avalue less than the effective area of the downstream side of the piston, and means mounted on the exterior of the casing for ymoving the piston rod with the piston and valve,

axially from the position wherein the piston valve is seated.

4. An automatic shut-ofi" valve for a fluid con-v duit system, comprising an inlet duct and an outlet duct, means forming a restricted flow orifice therebetween, hollow means having a movable partition defining an upstream chamber and a downstream chamber, said upstream chamber having a connection to said inlet duct, said connection comprising a second restricted flow orifice having a certain arearelationship to the first said orifice, means secured to said partition and extending through said upstream chamber and through said hollow means to move said partition Y from outside of the hollow means and to reduce the effective area of said partition in the upstream chamber to less than the effective area of saidv partition in the downstream chamber, means connecting said downstream chamber with said fluid outlet duct, a valve seat in said duct downstream of both said downstream chamber and said first orice, and a valveconne'cted to said movable partition and disposed in the downstream chamber, operated by movement of the partition and engageable with said seat to stop fluid iiow from the inlet duct and from the downstream chamber through the outlet duct upon movement of the partition in a downstream direction.

5. A valve according to claim 4 wherein said hollow means comprises a cylinder and said movable partition comprises a piston slidable inA the cylinder, said piston forming at either end thereof Within said cylinder said upstream and downstream chambers, and wherein said valve forms i a part of the downstream end of the piston.

6. In a metering shut-oi device including a housing, said housing having an inlet, means Aincluding a movable Wall defining rst and second chambers in said housing, said means for each of said chambers having a restricted opening communicating with said inlet, said openings being so related as to proportion oW from said inlet to both said chambers, said housing having an outlet communicating with vthe second chamber, a valve for said outlet connected to said wall for operation thereby, said valve being moved to closed position by said wall .during the terminal phase of the movement 'thereof in a direction to contract said s'econdfchamben said valve being so proportioned that when it is closed pressure on the eiective area'thereof exposed'to inlet pressure Will tend to hold it closed, and a `rod extending from said Vmovable kWall through the opposite wall of ysaid rst chamber, whereby the effective area of said 'Wall in the rst chamber is less than the effective area thereof in the second chamber, whereby, when the pressuresin said rst and second chambers are substantially equal and said valve is open, said wall is urged in a direction to contract said first chamber.

HERBERT W. WISHART.

References Cited in the le of this patent UNITED STATES 'PATENTS Number Name Date '2,103,962 Wineman Dec.`28, 1937 2,354,161 Waterman July 1'8, 19.44

FOREIGN PATENTS Number ICountry Date 123,149 Great Britain of 1912 v114,724 Germany of '1900 

